1. Field of the Invention
The invention relates generally to structure for mounting the free end or non-driven end of a rotary shaft mounted for operation within a kettle or other container, the invention particularly relating to an idler bearing mount for mounting the free end of the rotary shaft of a mixing agitator in relation to the inner wall of a kettle.
2. Description of the Prior Art
The processing of many materials including pharmaceuticals, cosmetics, foodstuffs and the like on an industrial scale often requires mixing or stirring operations and may, in some circumstances, require the scraping of inner wall surfaces of a kettle or other container within which materials are being processed. Scraping of wall surfaces is particularly necessary in many situations involving the heating and/or cooking of food materials in large cooking kettles. Mixing agitators which include a kettle wall scraping capability are disclosed in U.S. Pat. Nos. 4,571,091 to Pardo et al and 4,790,667 to Pardo et al. The Pardo et al agitators include rotary shafts mounted within a kettle with the shaft disposed horizontally. The structure of the Pardo et al agitators has proven to be particularly useful in the art with a substantial contribution of the usefulness of these agitators being the horizontal disposition of the rotary shaft of the agitators. The Pardo et al horizontal agitators can be mounted as is shown and described in the Pardo et al patents, the bearing structure described by Pardo et al allowing rapid disassembly of the agitator and bearing structure such that daily cleaning can be easily accomplished. Giusti, in U.S. Pat. No. 4,199,266, also describes a mixing agitator having a scraping capability wherein a rotary shaft is disposed horizontally within a cooking kettle, the shaft having a substantially circular agitator mounted thereon and wherein the agitator is formed of a pair of substantially annular semi-circular blades each having an internal segment-shaped web. The annular blades each carry a plurality of scrapers at their respective peripheries for scraping of internal surfaces of a kettle. Giusti also provides bearing structure for mounting of the non-driven end of the horizontal rotary shaft disclosed in U.S. Pat. No. 4,199,266. In situations where metal to metal contact must occur within or near the body of food materials being processed, bearings must operate within proscriptions of law relating to the use of lubricants within the body of food materials being processed. In order to avoid metal to metal contact in such processing situations, the prior art has included as one solution the use of plastic materials such as acetal interposed between metal surfaces to provide a necessary degree of lubrication. While the acetal spacing element, usually a bushing, could be readily replaced in these prior art situations, the bushing formed of acetal or other "plastic" material usually hardens in operation and becomes abrasive with the result that an idler pin forming a portion of the bearing structure is worn down. Since prior art idler bearing mounting structures do not allow for replacement of the idler pin, repair of a mount so configured is difficult with the result generally being the necessity for replacement of the entire kettle structure on which such bearings are permanently mounted.
The present invention provides an idler bearing mount particularly useful with horizontal agitators in the processing of materials which can include the heating and/or cooking of food materials in a kettle either with or without scraping of inner walls of the kettle. The present idler bearing mount is configured to allow rapid removal from a kettle so that the mount as well as the kettle and agitator can be disassembled easily for cleaning on a daily basis according to accepted sanitary standards. The present idler bearing mount of the invention is formed of materials which meet USDA standards for metal to metal contact within a body of food materials being processed and in food processing situations where the use of lubricants is regulated. The present idler bearing mount of the invention can also be readily and rapidly repaired in the event of excessive wear or damage to idler pin and/or bushing structure of the mount since the idler pin and bushing can be replaced. Accordingly, the present invention provides substantial performance, operational and cost advantages over those bearing structures previously used in the art for the mounting of a horizontally disposed rotary shaft of a mixing agitator structure used in a kettle or similar container for processing of materials including food materials, pharmaceuticals and the like.